Stadium

A stadium (plural stadiums or stadia) is a place or venue for (mostly) outdoor sports, concerts, or other events and consists of a field or stage either partly or completely surrounded by a tiered structure designed to allow spectators to stand or sit and view the event.
Pausanias noted that for about half a century the only event at the ancient Greek Olympic festival was the race that comprised one length of the stade at Olympia, where the word "stadium" originated.
Most of the stadiums with a capacity of at least 10,000 are used for association football. Other popular stadium sports include gridiron football, baseball, ice hockey, basketball, cricket, rugby union, rugby league, Australian-rules football, Gaelic football, rugby sevens, field lacrosse, bandy, athletics, hurling, field hockey, Kabaddi, and bullfighting. A large number of large sports venues are also used for concerts. Basketball is the most popular arena (or indoor stadium) sport in the world. Large race circuits and large horse racing tracks are not stadiums, but sports venues, because the entire playing surface can't be seen from the stands. For the difference, compare List of stadiums by capacity with List of sports venues by capacity.
The oldest known stadium is the one in Olympia, in the western Peloponnese, Greece, where the Olympic Games of antiquity were held from 776 BC. Initially 'the Games' consisted of a single event, a sprint along the length of the stadium. The stadion, a measure of length, may be related to the "Stadium", but the track at the Stadium at Olympia is longer than the conventional stadion. Greek and Roman stadiums have been found in numerous ancient cities, perhaps the most famous being the Stadium of Domitian, in Rome.
Stadiums in ancient Greece and Rome were built for different purposes, and at first only the Greeks built structures called "stadium"; Romans built structures called "Circus." Greek stadia were for foot races, whereas the Roman circus was for horse races. Both, however, had similar shapes and bowl-like areas around them for spectators. The Greeks also developed the theatre, with its seating arrangements foreshadowing those of modern stadiums. The Romans copied the theatre, then expanded it to accommodate larger crowds and more elaborate settings. The Romans also developed the double-sized round theatre called amphitheatre, seating crowds in the tens of thousands for gladiatorial combats and beast shows. The Greek stadium and theatre and the Roman circus and amphitheatre are all ancestral to the modern stadium.